1. Field of the Invention
This invention relates to a cogeneration system, and particularly to a cogeneration system having a plurality of power generation units each equipped with a generator and an internal combustion engine that drives the generator.
2. Description of the Related Art
In recent years, cogeneration systems have been developed that are equipped with an internal combustion engine-driven generator and are installed in an AC power supply line between a commercial power network and an electrical load for supplying or outputting power to the load in interconnection with the power network and also for supplying hot water or the like heated by the exhaust heat from the engine to a thermal load, i.e., a hot water tank that contains hot water.
When such a cogeneration system is installed in a facility, such as an apartment or condominium, that has a relatively large power demand and thermal demand, generally a plurality of generation units and hot water tanks are provided, as taught, for example, in Japanese Laid-Open Patent Application No. 2005-278231 (paragraphs 0012, 0015, FIG. 1, etc.). Specifically, each generation unit is coupled with one hot water tank and hence, the number of the units with tanks is increased.
However, if the multiple hot water tanks are installed as in the prior art, it causes increase in a space for the installation and also increase in thermal radiation (heat loss) from the tanks.